The invention relates generally to power line communication systems, and particularly to isolating signaling environments in a power line communication system.
Power line modems are used for transmitting data signals over the same wires that carry AC power. They have a wide range of uses, including allowing personal computers to communicate with each other, or with other household devices, without the need for separate data cables. There is a continuing need, however, for methods to facilitate more widespread use of power line modems.
In accordance with one aspect of the invention, power line data signals, which are carried over common wiring with power signals, are blocked while allowing the power signals to continue on the common wiring. The power line data signals are typically at a higher frequency than the power signals, and therefore the power line data signals are typically blocked by installing at least one filter (such as a low-pass filter, bandpass filter, or notch filter) on the common wiring. The at least one filter blocks the higher frequency power line data signals while allowing the lower frequency power signals to continue on the common wiring. Within a signaling environment, the at least one filter is typically installed between a power source and a number of outlets, and more typically between a circuit breaker and the number of outlets.
In accordance with another aspect of the present invention, power line data signals originating outside the signaling environment are blocked from entering the signaling environment. Specifically, the at least one filter is installed at an ingress point of the signaling environment. The at least one filter blocks power line data signals originating outside the signaling environment from entering the signaling environment. One advantage of blocking the power line data signals originating outside the signaling environment from entering the signaling environment is to prevent the power line data signals originating outside the signaling environment from interfering with power line communications within the signaling environment.
In accordance with yet another aspect of the present invention, power line data signals originating inside the signaling environment are blocked from leaving the signaling environment. Specifically, the at least one filter is installed at an egress point of the signaling environment. The at least one filter blocks power line data signals originating inside the signaling environment from leaving the signaling environment. One advantage of blocking power line data signals originating inside the signaling environment from leaving the signaling environment is to prevent power line communication within the signaling environment from interfering with power line communications in other signaling environments. Another advantage of blocking power line data signals originating inside the signaling environment from leaving the signaling environment is to prevent the interception and monitoring of power line communications from outside of the signaling environment.
In accordance with still another embodiment of the present invention, power line data signals originating outside the signaling environment are blocked from entering the signaling environment, and power line data signals originating inside the signaling environment are blocked from leaving the signaling environment. This may be accomplished, for example, by installing a single filter capable of blocking both incoming and outgoing power line data signals, or by installing separate ingress and egress filters for blocking the incoming and outgoing power line data signals, respectively.
In accordance with still another aspect of the invention, a filter for blocking power line data signals while allowing power signals to pass includes power side connectors for coupling the filter to power supply wires, outlet side connectors for coupling the filter to outlet wires, and filtering logic electrically coupled between the power side connectors and the outlet side connectors for blocking power line data signals while allowing power signals to pass through from the power side connectors to the outlet side connectors. The filtering logic may be coupled so as to block power line data signals received over the power side connectors from passing through to the outlet side connectors and/or block power line data signals received over the outlet side connectors from passing through to the power side connectors, while allowing power signals to pass through from the power side connectors to the outlet side connectors.
In accordance with still another aspect of the invention, a circuit breaker and filter are combined in the form of a circuit breaker that can replace an existing circuit breaker in a fuse box. The filter is typically coupled between the circuit breaker and the protected circuits. More specifically, such a device includes power side connectors for coupling to power supply wires, outlet side connectors for coupling to outlet wires, a circuit breaker electrically coupled between the power side connectors and the outlet side connectors, and filtering logic electrically coupled between the circuit breaker and the outlet side connectors for blocking power line data signals while allowing power signals to pass through from the power side connectors to the outlet side connectors. The filtering logic may be coupled so as to block power line data signals received over the power side connectors from passing through to the outlet side connectors and/or block power line data signals received over the outlet side connectors from passing through to the power side connectors, while allowing power signals to pass through from the power side connectors to the outlet side connectors.